When you purl, your yarn is in front and you needle should go in through the front 'leg' of the loop from right to left. You bring your yarn up over the top of the needle, counter-clockwise and then pull it through the loop away from you.

If you're purling through the back loop, you're bringing your right needle around to the back of the left needle and inserting your right needle into the back loop from left to right. This IS a real stitch, just not one that you do across the row.

I am making a conscious effort to make sure I don't give that tug.......either deliberate or subtle. The denises are a bit more glidey now after making conscious attempts at watching and after shorting my cord.....

I am wondering, though, whether tight knitting is the only problem. I think you'd have problems before the 6th row if your knitting was really that tight. Do you find that you are tense, or relaxed, when knitting?

I know I had this problem. My knitting was fine. I purled very tight mostly because I was holding the yarn very tight. My garter stitch was the BOMB. But my stockinette was very tight. I loosened up once I felt absolutely comfortable with purling. Another problem I had was that silly loop at the end of my knit row so I would purl the first stitch extra tight then subconsciously keep that extra tension through to the end of that row. But I started slipping that first stitch.